Every year 5,200 women and 3,600 men receive a diagnosis of multiple sclerosis (MS) in the United States. MS is the most common nontraumatic disabling neurological disorder in 20-59 year-olds. A variety of cognitive deficits are present in 43-65 percent of cases. Information processing speed and working memory (WM) deficits are common. The relationship between slowed information processing and other impaired cognitive functions such as verbal WM remains unclear. Slowed processing might account for remaining cognitive deficits. This study aims to 1) confirm processing speed and verbal WM deficits by comparing MS patients and healthy volunteers; 2) demonstrate significant correlations between these abilities; 3) determine if verbal WM impairments can be solely attributed to slowed processing by treating processing speed as a covariate in group comparisons; and 4) demonstrate differential deficits of verbal WM components processes (e.g., rehearsal, executive control) in group comparison across these components. If processing speed accounts for verbal WM deficits, a diffuse brain process resulting in global cognitive inefficiency would be supported. Alternatively, unique verbal WM deficits that are not attributable to the effects of cognitive slowing would support the idea of more focal neural disconnections, or the differential effects of information processing speed upon verbal WM components. These outcomes would have a clear impact on our understanding of the process by which MS cognitive deficits occur and help us better predict underlying brain systems involved. This is where I hope to direct my future research with a F32 award.